1. Field of the Invention
The present invention relates to a switching apparatus, and more particularly to a switching apparatus for carrying out a switching operation with reduced noises.
2. Description of the Related Art
Up until now, there have been proposed a wide variety of conventional switching apparatuses available for an electric device to be assembled in, for example, an automotive vehicle for the purpose of simple in construction and inexpensive in production cost.
One typical example of the conventional switching apparatus of this type is exemplified and shown in FIG. 8 as comprising a rear panel 600, a front panel 200 fixedly connected with the rear panel 600 and having a groove 220 formed therein; a switch device 500, and a push button 100. The front panel 200 includes a holder portion 210 and a cover plate 300 collectively defining the groove 220.
The switch device 500 has a stationary contact member, not shown in FIG. 8, fixedly mounted on the rear panel 600 and a movable contact member 510 movable with respect to the stationary contact member between a switch-on position where the movable contact member 510 is brought in contact with the stationary contact member to establish electrical connection between the movable contact member 510 and the stationary contact member and a switch-off position where the movable contact member 510 is brought out of contact with the stationary contact member to establish electrical disconnection between the movable contact member 510 and the stationary contact member. The switch device 500 further has a resilient member, not shown in FIG. 8, for resiliently urging the movable contact member 510 to have the movable contact member 510 move with respect to the stationary contact member toward the switch-off position.
The push button 100 has a pushed portion 110 and a flange portion 140 extending radially and outwardly of and integrally formed with the pushed portion 110. The flange portion 140 has a first flange section 140a and a second flange section 140b opposing to and spaced apart from the first flange section 140a across the pushed portion 110. The first flange section 140a has a horn projection 120. The horn projection 120 protrudes in one direction and has a center axis. The push button 100 is supported by the front panel 200 with the horn projection 120 loosely received in the groove 220. The push button 100 is pivotable around the center axis of the horn projection 120 in two different directions including a button-pushed direction D1 to have the second flange section 140b move the movable contact member 510 with respect to the stationary contact member toward the switch-on position and a button-released direction D2 to have the second flange section 140b move the movable contact member 510 with respect to the stationary contact member toward the switch-off position with the aid of the resilient member.
The conventional switching apparatus constructed as previously mentioned, however, encounters a drawback that the second flange section 140b tends to collide against the front panel 200 immediately after the movable contact member 510 is moved by the resilient member to the switch-off position because of the fact that the push button 100 is pivoted around the center axis of the horn projection 120, which is loosely received in the groove 220. Furthermore, the push button 100 and the front panel 200 are made of a plastic material and have resonant frequencies in high and/or middle frequency ranges. The fact that the push button 100 and the front panel 200 are made of a plastic material and the push button 100 is loosely received in the groove 220 of the front panel 200 leads to the fact that the collision of the second flange section 140b of the push button 100 against the front panel 200 causes the push button 100 and the front panel 200 to be resonantly oscillated in high and/or middle frequency ranges, thereby generating unpleasant noises to operators' ears.